OFFSET
1,1
COMMENTS
Primes p such that (p^2 + p*q)/(p + 1) is not integer for all primes q.
Primes p such that d1 - 1, d2 - 1, .. are not primes where d1, d2, .. are all divisors of p - 1.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
11 is in this sequence because (11 - 1)/1 - 1 = 9, (11 - 1)/2 - 1 = 4, (11 - 1)/5 - 1 = 1, (11 - 1)/10 - 1 = 0 are nonprimes and 11 is prime.
PROG
(PARI) lista(nn) = {forprime (p=2, nn, ok = 1; for (k=1, p-1, x = (p-1)/k - 1; if (denominator(x)==1 && isprime(x), ok = 0; break); ); if (ok, print1(p, ", ")); ); } \\ Michel Marcus, Nov 02 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, Oct 24 2015
EXTENSIONS
Name edited by Franklin T. Adams-Watters, Oct 31 2015
STATUS
approved